IMS Conversations across different regions

There are 3 IMS Regions say IMS1, IMS2, IMS3
There are 4 transactions say IMS1A in IMS1(local), IMS2A in IMS2, IMS3X1 and IMS3X2 in IMS3. All are conversational transactions and interact with a User through the LTERM. Each one processes different user commands and for some particular commands use immediate switching to the appropriate transaction. Th following are the cases of the switch.

1A can switch to 2A or X1
2A can switch to 1A or X2
X1 switches to 1A
X2 switches to 2A

All switches are immediate program switches

1A and 2A are defined as RMT in IMS3.
2A is defined as RMT in IMS1.
1A is defined as RMT in IMS2.
X1 is defined as RMT im IMS1
X2 is defined as RMT in IMS2

The following are the scenarios
1) If a User logs to IMS1, invokes 1A the types a command which causes 1A to switch to X1. X1 returns a screen to the User and when the user gives another appropriate command X1 switches to A1. A1 returns the screen to the User

2) User logs to IMS1, invokes 1A, gives a command to switch to 2A, now 1A swithces to 2A and 2A returs a screen. The user then commands 2A to switch to X2 which again happens but the user LTERM hangs up at this point.

My guess is X2 tries to returns the screen to IMS1 and its not getting routed to IMS1 since X2 is not defined as RMT in IMS1.

is this to be handled in the code or is there some MSC setup that needs to be done ?